On Monday, June 21, 2010, I wrote:
> On Monday, June 21, 2010, David Henningsson wrote:
> > Sounds fair enough to me, for now. I think I'll use CMake for a while
> > now and see if I run into trouble. My first impression is that I like it
> > - it seems to be more modern and adjusted for today's needs, compared to
> > the ancient autotools.
> >
> > Btw, I've committed an updated CMakeLists.txt and moved files into
> > "drivers" subdir (just audio and midi drivers) and an "rvoice" dir (for
> > the voice renderer stuff) which will get more files in it soon.
> >
> > // David
>
> Thanks, it builds OK now!
>
> I've noticed that there is a new option to enable D-Bus client support, for
> rtkit. Do you dare to include it in the CMake build system?
Actually, this is an opportunity for explaining some CMake concepts, adding a
new feature to the CMake build system. So here is a brief HOWTO and a patch.
Please ask questions if there is something unclear, and feel free to commit
the changes after some testing and your own customization.
Regards,
Pedro
Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt (revision 298)
+++ CMakeLists.txt (working copy)
@@ -61,6 +61,7 @@
option ( enable-dart "compile DART support (if it is available)" on )
option ( enable-readline "compile readline lib line editing (if it is available)" on )
option ( enable-lash "compile LASH support (if it is available)" on )
+option ( enable-dbus "compile DBUS support (if it is available)" on )
# Initialize the library directory name suffix.
if ( CMAKE_SIZEOF_VOID_P EQUAL 8 )
@@ -325,6 +326,13 @@
set ( LADCCA_SUPPORT ${LADCCA_FOUND} )
endif ( enable-ladcca )
+set ( DBUS_SUPPORT )
+set ( DBUS_LIBRARIES )
+if ( enable-dbus )
+ pkg_check_modules ( DBUS dbus-1>=1.0.0 )
+ set ( DBUS_SUPPORT ${DBUS_FOUND} )
+endif ( enable-dbus )
+
# General configuration file
configure_file ( ${CMAKE_SOURCE_DIR}/src/config.cmake
${CMAKE_BINARY_DIR}/config.h )
Index: cmake_admin/report.cmake
===================================================================
--- cmake_admin/report.cmake (revision 298)
+++ cmake_admin/report.cmake (working copy)
@@ -11,6 +11,12 @@
message ( "libsndfile: no (raw audio file rendering only)" )
endif ( LIBSNDFILE_SUPPORT )
+if ( DBUS_SUPPORT )
+ message ( "D-Bus: yes" )
+else ( DBUS_SUPPORT )
+ message ( "D-Bus: no" )
+endif ( DBUS_SUPPORT )
+
if ( PULSE_SUPPORT )
message ( "PulseAudio: yes" )
else ( PULSE_SUPPORT )
Index: src/CMakeLists.txt
===================================================================
--- src/CMakeLists.txt (revision 298)
+++ src/CMakeLists.txt (working copy)
@@ -54,6 +54,11 @@
set ( fluid_coremidi_SOURCES drivers/fluid_coremidi.c )
endif ( COREMIDI_SUPPORT )
+if ( DBUS_SUPPORT )
+ set ( fluid_dbus_SOURCES fluid_rtkit.c fluid_rtkit.h )
+ include_directories ( ${DBUS_INCLUDEDIR} ${DBUS_INCLUDE_DIRS} )
+endif ( DBUS_SUPPORT )
+
if ( JACK_SUPPORT )
set ( fluid_jack_SOURCES drivers/fluid_jack.c )
include_directories ( ${JACK_INCLUDEDIR} ${JACK_INCLUDE_DIRS} )
@@ -172,6 +177,8 @@
${PORTAUDIO_LIBRARY_DIRS}
${LIBSNDFILE_LIBDIR}
${LIBSNDFILE_LIBRARY_DIRS}
+ ${DBUS_LIBDIR}
+ ${DBUS_LIBRARY_DIRS}
)
add_library ( libfluidsynth SHARED
@@ -179,6 +186,7 @@
${fluid_coreaudio_SOURCES}
${fluid_coremidi_SOURCES}
${fluid_dart_SOURCES}
+ ${fluid_dbus_SOURCES}
${fluid_jack_SOURCES}
${fluid_lash_SOURCES}
${fluid_ladspa_SOURCES}
@@ -218,13 +226,14 @@
${PULSE_LIBRARIES}
${PORTAUDIO_LIBRARIES}
${LIBSNDFILE_LIBRARIES}
+ ${DBUS_LIBRARIES}
${READLINE_LIBS}
${DART_LIBS}
${COREAUDIO_LIBS}
${COREMIDI_LIBS}
${WINDOWS_LIBS}
${MidiShare_LIBS}
- ${LIBFLUID_LIBS}
+ ${LIBFLUID_LIBS}
)
# ************ CLI program ************
Index: src/config.cmake
===================================================================
--- src/config.cmake (revision 298)
+++ src/config.cmake (working copy)
@@ -19,6 +19,9 @@
/* Define if building for Mac OS X Darwin */
#cmakedefine DARWIN @DARWIN@
+/* Define if D-Bus support is enabled */
+#cmakedefine DBUS_SUPPORT @DBUS_SUPPORT@
+
/* Define to enable FPE checks */
#cmakedefine FPE_CHECK @FPE_CHECK@
How to add a new feature to the CMake build system
==================================================
Let's explain this issue with an example. We are adding D-Bus support to
FluidSynth as an optional feature, conditionally adding source files that
require this feature. The first step is to add a macro "option()" to the main
CMakeLists.txt file, the one that is located at the fluidsynth root directory.
file CMakeLists.txt, line 64:
option ( enable-dbus "compile DBUS support (if it is available)" on )
Now, let's check if the dbus-1 library and headers are installed, using
pkg-config:
file CMakeLists.txt, lines 329-334:
set ( DBUS_SUPPORT )
set ( DBUS_LIBRARIES )
if ( enable-dbus )
pkg_check_modules ( DBUS dbus-1>=1.0.0 )
set ( DBUS_SUPPORT ${DBUS_FOUND} )
endif ( enable-dbus )
The two first lines clear the values of the CMake variables DBUS_LIBRARIES and
DBUS_SUPPORT. If the value of the option "enable-dbus" is true, then the macro
pkg_check_modules() is used to test a package named "dbus-1" with version 1.0.0
or later. This macro automatically defines the variables DBUS_LIBRARIES,
DBUS_INCLUDEDIR, DBUS_FOUND and others. The value of the last one is assigned
to our variable DBUS_SUPPORT for later use.
There is a report to summarize the performed checks and the enabled features
after the configuration steps, so let's add a line in this report regarding the
D-Bus support.
file cmake_admin/report.cmake, lines 14-18:
if ( DBUS_SUPPORT )
message ( "D-Bus: yes" )
else ( DBUS_SUPPORT )
message ( "D-Bus: no" )
endif ( DBUS_SUPPORT )
The variable DBUS_SUPPORT is available for the CMake files, but we want to make
it available to the compilers as well, to conditionally build code using
"#ifdef DBUS_SUPPORT". This can be done adding a line to the config.cmake file:
file src/config.cmake, lines 22-23:
/* Define if D-Bus support is enabled */
#cmakedefine DBUS_SUPPORT @DBUS_SUPPORT@
The file config.cmake will be processed at configure time, producing a header
file "config.h" in the build directory with this content, if the dbus support
has been enabled and found:
/* Define if D-Bus support is enabled */
#define DBUS_SUPPORT 1
Finally, we can add the new source files to the build system for the compiler
target with the macro add_library(), and the libraries for the linker target
with the macros link_directories() and target_link_libraries().
file src/CMakeLists.txt, lines 57-60
if ( DBUS_SUPPORT )
set ( fluid_dbus_SOURCES fluid_rtkit.c fluid_rtkit.h )
include_directories ( ${DBUS_INCLUDEDIR} ${DBUS_INCLUDE_DIRS} )
endif ( DBUS_SUPPORT )
file src/CMakeLists.txt, lines 163-197
link_directories (
...
${DBUS_LIBDIR}
${DBUS_LIBRARY_DIRS}
)
add_library ( libfluidsynth SHARED
...
${fluid_dbus_SOURCES}
...
)
file src/CMakeLists.txt, lines 163-197
target_link_libraries ( libfluidsynth
...
${DBUS_LIBRARIES}
...
)
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